Boosters Protect Against Severe Covid for Six Months, Study Says

A Covid-19 vaccine booster shot protects people from becoming severely ill or dying and its efficacy lasts for six months, according a study published in the Journal of the American Medical Association, underscoring the importance of additional jabs as the world moves to coexist with the virus.

The mRNA booster vaccines -- made by drugmakers Pfizer Inc. and BionTech SE, or Moderna Inc. -- were most effective in cutting the rate of people with severe Covid, scoring an estimated 87%, and there was no evidence of their effect waning within six months, the study found. Inactivated booster vaccines ...